Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO

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000
FXUS63 KEAX 191746
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1246 PM CDT Fri Sep 19 2014

.UPDATE...
Issued at 932 AM CDT FRI SEP 19 2014

Day 3 of trying to get rid of this pesky stratus. Inspection of
current TOP Raob and latest BUFR soundings indicate the moisture
will remain trapped under the low-level inversion for the better part
of today. 12z NAM/RAP condensation pressure deficit progs also hold
onto this cloud cover over the western 1/2 of the CWA into at least
the early afternoon hours....and it is not unreasonable to expect it to
last until sunset like yesterday and then rapidly dissipate. With
this in mind will hold onto the cloud skies into the early afternoon
before scattering them out. Also means lowering max temperatures
across the western portion of the CWA.

&&

.DISCUSSION...
Issued at 417 AM CDT FRI SEP 19 2014

Water vapor imagery this morning shows a moderately amplified
patter in place across the Nation with the currently prevailing East
CONUS trough inducing a bit of a cool northwest flow across our
region of the country. This has helped keep a cool surface ridge in
place across the Lower Missouri River Valley for the past couple of
days. However, a shortwave trough moving through the Pacific
Northwest this morning has begun generating lee-side troughing across
the Northern Plains. As this trough progresses east the resulting warm
air advection across the Southern and Central Plains will bring a
warm front north on the back side of the exiting surface ridge today.
This should allow temperatures to rebound from the fall like
temperatures they have been wallowing in for the past couple of days
back towards or above normal --Upper 70s for this time of year--.

Next chance at rain looks to arrive Saturday as the Pacific
Northwest shortwave zips east through the Northern Plains, dragging
a cold front south into the Central Plains Saturday. Temperatures
ahead of the front Saturday will be warm as afternoon highs in the
80s continue to remind us that Summer is not over yet. This will
set the stage across Eastern Kansas and Northern Missouri by the
afternoon hours for some thunderstorms activity, though it might not
be much. Instability during the afternoon hours is advertised to be
rather substantial as MUCAPE values over 3000+ J/KG are advertised
for the afternoon, but shear is looking a little weak with only 20
to 30 knots of 0-6KM. However, a variety of models have trended
towards a much drier solution over the past few days as the upper
level dynamics from the shortwave seem to remain removed from our
section of the country, more focused across Iowa and into northern
Illinois. So, while we look to have good instability and at least
marginally sufficient shear, the lift --and consequently the
advertised thunderstorms-- look to be post frontal; ultimately
significantly restricting our potential for storms. Have kept high-
end chance POPs in place for Saturday afternoon and evening, but have
continued the trend of restricting POPs before noon. This should keep
the overall potential for severe weather low, though any storms that
might bubble up in the early or mid-afternoon hours will need close
watching.

With the passage of a cold front Saturday night temperatures will
cool off a little as we move through the rest of the weekend and
into the next work week as a Pacific surface ridge slides into and
across the region. Currently, temperatures are expected to range
around seasonally normal --through the 70s-- through much of the week
as the Pacific surface ridge wallows around the eastern half of the
CONUS; similar to this past weeks pattern. While this will likely
keep temperatures around normal, the advertised highs in the 70s might
be the max temperatures that can be expected due to the potential for
storms and cloud cover. Like this past weeks weather, next weeks
storms could set up just to our west as any little shortwave trough
moving through the amplified flow will work on the backside of the
high, inducing some stormy activity across Kansas north into
Nebraska. Have kept a verity of slight chance to chance POPs in
across Eastern Kansas and parts of Northwest Missouri from Tuesday
night through Wednesday, allowing the POPs to spread east a bit into
Thursday as the surface ridge shifts east.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
Issued at 1245 PM CDT FRI SEP 19 2014

Extensive IFR/low end MVFR stratus deck covering eastern KS and much
of western MO will gradually thin as well as erode from the west.
It`s certainly possible that the center portion of the stratus deck
will linger over west central MO till sunset and then dissipate
shortly after sunset...just like yesterday. With the low-level
moisture remaining trapped under the inversion, any clearing over
western MO and eastern KS may last for the evening hours only. The 12z
NAM 925mb condensation pressure deficit prog indicates LIFR cigs and
MVFR visibilities will reform after midnight and which seems
reasonable. Expect these conditions to abate by mid morning as the
inversion erodes while winds veer to the southwest.

A cold front will drop south into northern MO Saturday morning. Any
associated convection will likely be dissipating as it enters
northern MO. A better chance for convection will develop Saturday
afternoon across northern MO.


&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&

$$

UPDATE...MJ
DISCUSSION...Cutter
AVIATION...MJ





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